This invention relates to telecommunications, and more specifically, to a device and method for the all-optical simultaneous multiple reproduction of optical signals.
In a variety of optical data transmission systems, it is necessary to reproduce multiple copies of an original optical signal. Conventionally this is done in one of two ways, either by means of optical-to-electrical-to-optical (xe2x80x9cOEOxe2x80x9d) data multiplication, or by some type of interferometric device. OEO methods are costly in terms of the resources and complicated infrastructure used. As well, OEO methods are format and bit rate sensitive. If data signal multiplication can be done all optically, it saves significant time, space and power resources that must be used in OEO processes. However, using interferometric devices, even if the ideal 100% efficiency can be reached, which is ambitious, the power of the input signal is split among the various copies of the signal. If the input extinction ratio is low to begin with, this could severely limit the copies of the input signal that can be made.
What is needed in the art is a means of multiplying lightwave signals without resort to OEO methods, and without constraints on multiplication due to input signal power limitations.
What is further needed is a means of making numerous copies of an input signal, each copy having an extinction ratio greater than or equal to that of the original input signal.
A single device for amplifying and multiplying an optical signal is presented. The device is an InP-semiconductor-based amplified multimode interferometer. The three main sections of the device are an input port, an interference and amplification region and N output ports. The input port is a single channel waveguide. The interference and amplification section supports a large number of modes which interfere with one another. By carefully choosing the length of the interference/amplification region to correspond to the constructive interference condition for N equally spaced channel modes, we can reproduce N amplified signals. In an alternate embodiment, by shaping the gain region into a cross pattern, corner reflections and consequent side channel signal distortion in the output can be minimized.